This property is a comma-separated list of words used to identify subject lines in mail items that were undeliverable.
IDL Definition
[propget]
HRESULT NDRSubjectKeywords( [out, retval] VARIANT *pVal /*VT_BSTR*/ );
[propput]
HRESULT NDRSubjectKeywords( [in] BSTR newVal);Type
BSTR
Default
"Undeliverable, nondeliverable, Nondelivery, Unable, Cannot, Return"